The present exemplary embodiment relates to a mast safety restraint mechanism. It finds particular application in conjunction with a cable winch operated portably mast assembly, and it will be described with particular reference thereto. However, it is to be appreciated that the present exemplary embodiment is also amenable to other like applications.
Portable masts systems are utilized in many different capacities, including civilian, industrial and military applications, throughout the world. Quick erecting and portable masts are particularly suited for applications wherever there is a need for masts requiring fast setup and teardowns with minimum manpower and effort. In addition to numerous military applications, including target acquisitions, surveillance and field communications, quick and portable erecting masts are utilized commercially to support a variety of payload types such as antennas, satellite dishes, elevated testing equipment, floodlights and cameras. Free standing masts can be installed on a wide variety of terrain but can also be erected on vehicles and shelters.
Generally, the body of the mast includes a series of stackable tubes that typically comprise cylindrical shaped bodies, each tube having a generally hollow interior configured to be breech loaded. Breech loading typically includes stacking each tube from the base such that each additional tube added to the mast extends the height upwards. The plurality of stackable tubes is generally configured to be concentrically engaged to one another. This arrangement can comprise any number of tubes, wherein each tube includes a generally similar sized diameter, and is commonly known in the art. Portable masts are supported by a system of guy wires, base plates, stakes, and a support base. The plurality of tubes that comprises a portable mast assembly is manually breech loaded by a user to extend a top tube from the support base such as a tripod base to a desired height. The guy wires can be attached to the top tube of the mast assembly and are staked to the ground at positions surrounding the tripod base.
Portable masts can include carriage assemblies that are known to be manually or automatically operated using a cable winch arrangement. Particularly, a cable winch mast includes a winch mechanism positioned at a user level of the mast assembly for translating the carriage assembly to any position between a retracted position and an extended position. Cable winch masts are useful as field-erected masts due to their lightweight mobility and can be quickly erected relative to other mast systems.
The carriage assembly is used to translate a desired payload, such as lighting assemblies, communication antennae, satellite dishes, cameras or the like, from the support base to a desired elevation along the extended portable mast assembly. The carriage assembly is configured to move along the tubes of the mast while supporting the payload. Generally, the carriage is attached to a cable, which is wound around a pulley at the top tube and a spool of the winch mechanism located adjacent to the support base of the mast assembly. Rotation of the spool acts to retract the cable and lift the carriage and payload upwards along the erected mast tubes.
However, the cable is subject to various loads and therefore risks failure due to cable fray, breakage or becoming disconnected from a connection to the winch mechanism or carriage assembly. Upon cable failure, the carriage assembly and associated payload, if elevated at the time of cable failure, may crash down upon the support base or winch mechanism and cause damage or injury to surrounding people and property.
Therefore, there is a need to provide a carriage assembly that is capable of maintaining its elevation along the erected mast tubes in the event of cable failure. There is also a need to provide a mast safety restraint mechanism to limit the risk and scope of damage caused by cable failure.